IBS – Symptoms

IBS - Symptoms

Irritable bowel syndrome has a variety of gastrointestinal (GI) and non-GI signs and symptoms.  Since they can be vague, and have similar signs and symptoms as other GI conditions, doctors have been encouraged to use a classification symptom to identify people with IBS.

Most people with IBS present with chronic or recurrent abdominal pain with a change in stool form.  The Rome III criteria is currently used by doctors to make a definitive diagnosis.  To be called or diagnosed with irritable bowel syndrome, the onset of symptoms must have occurred in the past six months with the following characteristics:

* Recurrent abdominal pain or discomfort at least 3 days per month in the last 3 months that is associated with two or more of the following:
o Improvement with defecation
o Onset associated with a change in frequency of stool
o Onset associated with a change in form (appearance of stool)

The following are supportive symptoms that may be associated with the diagnostic symptoms above:

* Less than 3 bowel movements per week or greater than 3 bowel movements per day

* Abnormal stool form (lumpy-hard stool or loose-watery stool)

* Defecation

* Straining

* Urgency

* A feeling of incomplete evacuation

* Passing of mucus

* Bloating

The old system of classification (Rome II) based IBS diagnosis on the frequency of stools.  It has been found that people with IBS can have both frequent and infrequent bowel movements, and the stool form can be watery, loose, or hard.  The Rome III criteria is based on the results of recent studies that demonstrate stool form is the best predictor of predominant bowel habit as well as a better reflection of intestinal transit time.

Therefore, the following four subtypes of IBS from the Rome III criteria are based on bowel habit (stool form):

* IBS with constipation (IBS-C):  Describes patients with greater than or equal to 25% of stools hard and lumpy and less than 25% loose (mushy) or watery

* IBS with diarrhea (IBS-D): Describes patients with greater than  or equal to 25% of stools loose and watery and less than 25% hard or lumpy

* Mixed IBS (IBS-M): Describes patients with greater than or equal to 25% of stools hard and lumpy and greater than or equal to 25% of stool loose or watery.

* Untyped IBS (IBS-U): Patients are placed in this category if not enough stools are abnormal to meet criteria for any other subtype.

IBS-M is the subtype most frequently encountered by primary care doctors.  Subtypes frequently change, and 29% of patients with IBS-C move to IBS-D within one year.  Because symptoms can change frequently, IBS may be informally described as “IBS with diarrhea” or “IBS with constipation”.  IBS-C patients have more overall symptoms, particularly bloating, than IBS-D patients.

Other Non-GI symptoms
People with IBS often visit the physician with symptoms that are not directly related to the GI system.  These symptoms are very frequent, and may occur in 11% to 81% of IBS patients, depending on the symptom.  The non-GI symptoms include back pain, headache, fatigue, muscle pain, urinary frequency, dizziness, and pain with intercourse.  It is common to see other disorders that are associated with IBS.  These disorders include reflux disease, heartburn, fibromyalgia, chronic fatigue syndrome, chronic pelvic pain, temporomandibular joint disorder (TMJ) disorder, and interstitial cystitis.  There is also a high prevalence of somatization disorder in people with IBS.


Lehrer J. Irritable Bowel Syndrome. eMedicine [web page]. Aug 8 2007; www.emedicine.com/med/TOPIC1190.HTM. Accessed June 24, 2008.

Videlock EJ, Chang L. Irritable bowel syndrome: current approach to symptoms, evaluation, and treatment. Gastroenterol Clin North Am. Sep 2007;36(3):665-685, x.